1. Field of the Invention
The present invention relates to a clutch device for a power tool which is capable of switching a torque mode or a drilling mode.
2. The Prior Arts
A conventional output-torque-adjustable power tool, such as a power drill, uses a rotating torque member to set up the torque values and the output modes. The conventional way to achieve the above mentioned torque setting function is to provide a clutch device in the power tool. Thus, when the output torque from the gear box driven by the motor is smaller than the input torque from the main shaft, the clutch device is disengaged and switched to an idle state. When the power tool is switched to the drilling mode, the clutch device cannot be disengaged, thereby providing the maximum output torque.
The conventional clutch device uses beads or rollers to assemble the clutch device within the power tool so that the beads or rollers have to be precisely installed in the power tool. The material for the beads and the rollers are different from that of the clutch. Thus, the wearing for the two different materials is different and it affects the function of the power tool.
Another improved clutch device uses two pins to assemble the clutch device within the power tool. The pins extend through the case of the power tool and insert into the side of the clutch. However, the pins bear a heavy load and do not provide enough support to the clutch device.